The present invention relates to an magneto-optical media for effecting reading out signals by utilizing the magneto-optical effect (Kerr effect).
In a conventional magneto-optical media, as can be seen in the disclosure of the Japanese Patent Application No. 27458/87, there has been such consideration that, in the Kerr effect read-out system by utilizing the reflected light from a magneto-optical media, the signal versus noise ratio (S/N ratio) is proportional to log (.theta..multidot.R) (where .theta. denotes a Kerr rotation angle and R the rate of the reflected light), and the optimization of the refractive index and the film thickness of each thin film layer has been carried out with respect to S/N ratio, the protective characteristics, heat conducting characteristics, etc.
However, in a mass-produced magneto-optical head, since the phase difference between P polarized light and S polarized light has at worst the fluctuation of about .+-.15 degrees, a suitable S/N ratio cannot be obtained when the Kerr effect read-out is carried out even in a magneto-optical media most suitably designed by using the conventional technology. Therefore, the present invention intends to solve such a problem, and provides a magneto-optical media most suitably formed in such a manner that a S/N ratio is sufficient to enable high density recording and reading at the environmental temperature in a mass-produced drive.